package x.org.bouncycastle.crypto.digests;


import x.org.bouncycastle.crypto.ExtendedDigest;
import x.org.bouncycastle.crypto.util.Pack;
import x.org.bouncycastle.util.Memoable;

/**
 * Base class for SHA-384 and SHA-512.
 */
public abstract class LongDigest implements ExtendedDigest, Memoable {
	private static final int BYTE_LENGTH = 128;

	private byte[] xBuf;
	private int xBufOff;

	private long byteCount1;
	private long byteCount2;

	protected long H1, H2, H3, H4, H5, H6, H7, H8;

	private long[] W = new long[80];
	private int wOff;

	/**
	 * Constructor for variable length word
	 */
	protected LongDigest() {
		xBuf = new byte[8];
		xBufOff = 0;

		reset();
	}

	/**
	 * Copy constructor. We are using copy constructors in place of the
	 * Object.clone() interface as this interface is not supported by J2ME.
	 */
	protected LongDigest(LongDigest t) {
		xBuf = new byte[t.xBuf.length];

		copyIn(t);
	}

	protected void copyIn(LongDigest t) {
		System.arraycopy(t.xBuf, 0, xBuf, 0, t.xBuf.length);

		xBufOff = t.xBufOff;
		byteCount1 = t.byteCount1;
		byteCount2 = t.byteCount2;

		H1 = t.H1;
		H2 = t.H2;
		H3 = t.H3;
		H4 = t.H4;
		H5 = t.H5;
		H6 = t.H6;
		H7 = t.H7;
		H8 = t.H8;

		System.arraycopy(t.W, 0, W, 0, t.W.length);
		wOff = t.wOff;
	}

	public void update(byte in) {
		xBuf[xBufOff++] = in;

		if (xBufOff == xBuf.length) {
			processWord(xBuf, 0);
			xBufOff = 0;
		}

		byteCount1++;
	}

	public void update(byte[] in, int inOff, int len) {
		//
		// fill the current word
		//
		while ((xBufOff != 0) && (len > 0)) {
			update(in[inOff]);

			inOff++;
			len--;
		}

		//
		// process whole words.
		//
		while (len > xBuf.length) {
			processWord(in, inOff);

			inOff += xBuf.length;
			len -= xBuf.length;
			byteCount1 += xBuf.length;
		}

		//
		// load in the remainder.
		//
		while (len > 0) {
			update(in[inOff]);

			inOff++;
			len--;
		}
	}

	public void finish() {
		adjustByteCounts();

		long lowBitLength = byteCount1 << 3;
		long hiBitLength = byteCount2;

		//
		// add the pad bytes.
		//
		update((byte) 128);

		while (xBufOff != 0) {
			update((byte) 0);
		}

		processLength(lowBitLength, hiBitLength);

		processBlock();
	}

	public void reset() {
		byteCount1 = 0;
		byteCount2 = 0;

		xBufOff = 0;
		for (int i = 0; i < xBuf.length; i++) {
			xBuf[i] = 0;
		}

		wOff = 0;
		for (int i = 0; i != W.length; i++) {
			W[i] = 0;
		}
	}

	public int getByteLength() {
		return BYTE_LENGTH;
	}

	protected void processWord(byte[] in, int inOff) {
		W[wOff] = Pack.bigEndianToLong(in, inOff);

		if (++wOff == 16) {
			processBlock();
		}
	}

	/**
	 * adjust the byte counts so that byteCount2 represents the upper long (less
	 * 3 bits) word of the byte count.
	 */
	private void adjustByteCounts() {
		if (byteCount1 > 0x1fffffffffffffffL) {
			byteCount2 += (byteCount1 >>> 61);
			byteCount1 &= 0x1fffffffffffffffL;
		}
	}

	protected void processLength(long lowW, long hiW) {
		if (wOff > 14) {
			processBlock();
		}

		W[14] = hiW;
		W[15] = lowW;
	}

	protected void processBlock() {
		adjustByteCounts();

		//
		// expand 16 word block into 80 word blocks.
		//
		for (int t = 16; t <= 79; t++) {
			W[t] = Sigma1(W[t - 2]) + W[t - 7] + Sigma0(W[t - 15]) + W[t - 16];
		}

		//
		// set up working variables.
		//
		long a = H1;
		long b = H2;
		long c = H3;
		long d = H4;
		long e = H5;
		long f = H6;
		long g = H7;
		long h = H8;

		int t = 0;
		for (int i = 0; i < 10; i++) {
			// t = 8 * i
			h += Sum1(e) + Ch(e, f, g) + K[t] + W[t++];
			d += h;
			h += Sum0(a) + Maj(a, b, c);

			// t = 8 * i + 1
			g += Sum1(d) + Ch(d, e, f) + K[t] + W[t++];
			c += g;
			g += Sum0(h) + Maj(h, a, b);

			// t = 8 * i + 2
			f += Sum1(c) + Ch(c, d, e) + K[t] + W[t++];
			b += f;
			f += Sum0(g) + Maj(g, h, a);

			// t = 8 * i + 3
			e += Sum1(b) + Ch(b, c, d) + K[t] + W[t++];
			a += e;
			e += Sum0(f) + Maj(f, g, h);

			// t = 8 * i + 4
			d += Sum1(a) + Ch(a, b, c) + K[t] + W[t++];
			h += d;
			d += Sum0(e) + Maj(e, f, g);

			// t = 8 * i + 5
			c += Sum1(h) + Ch(h, a, b) + K[t] + W[t++];
			g += c;
			c += Sum0(d) + Maj(d, e, f);

			// t = 8 * i + 6
			b += Sum1(g) + Ch(g, h, a) + K[t] + W[t++];
			f += b;
			b += Sum0(c) + Maj(c, d, e);

			// t = 8 * i + 7
			a += Sum1(f) + Ch(f, g, h) + K[t] + W[t++];
			e += a;
			a += Sum0(b) + Maj(b, c, d);
		}

		H1 += a;
		H2 += b;
		H3 += c;
		H4 += d;
		H5 += e;
		H6 += f;
		H7 += g;
		H8 += h;

		//
		// reset the offset and clean out the word buffer.
		//
		wOff = 0;
		for (int i = 0; i < 16; i++) {
			W[i] = 0;
		}
	}

	/* SHA-384 and SHA-512 functions (as for SHA-256 but for longs) */
	private long Ch(long x, long y, long z) {
		return ((x & y) ^ ((~x) & z));
	}

	private long Maj(long x, long y, long z) {
		return ((x & y) ^ (x & z) ^ (y & z));
	}

	private long Sum0(long x) {
		return ((x << 36) | (x >>> 28)) ^ ((x << 30) | (x >>> 34))
				^ ((x << 25) | (x >>> 39));
	}

	private long Sum1(long x) {
		return ((x << 50) | (x >>> 14)) ^ ((x << 46) | (x >>> 18))
				^ ((x << 23) | (x >>> 41));
	}

	private long Sigma0(long x) {
		return ((x << 63) | (x >>> 1)) ^ ((x << 56) | (x >>> 8)) ^ (x >>> 7);
	}

	private long Sigma1(long x) {
		return ((x << 45) | (x >>> 19)) ^ ((x << 3) | (x >>> 61)) ^ (x >>> 6);
	}

	/*
	 * SHA-384 and SHA-512 Constants (represent the first 64 bits of the
	 * fractional parts of the cube roots of the first sixty-four prime numbers)
	 */
	static final long K[] = { 0x428a2f98d728ae22L, 0x7137449123ef65cdL,
			0xb5c0fbcfec4d3b2fL, 0xe9b5dba58189dbbcL, 0x3956c25bf348b538L,
			0x59f111f1b605d019L, 0x923f82a4af194f9bL, 0xab1c5ed5da6d8118L,
			0xd807aa98a3030242L, 0x12835b0145706fbeL, 0x243185be4ee4b28cL,
			0x550c7dc3d5ffb4e2L, 0x72be5d74f27b896fL, 0x80deb1fe3b1696b1L,
			0x9bdc06a725c71235L, 0xc19bf174cf692694L, 0xe49b69c19ef14ad2L,
			0xefbe4786384f25e3L, 0x0fc19dc68b8cd5b5L, 0x240ca1cc77ac9c65L,
			0x2de92c6f592b0275L, 0x4a7484aa6ea6e483L, 0x5cb0a9dcbd41fbd4L,
			0x76f988da831153b5L, 0x983e5152ee66dfabL, 0xa831c66d2db43210L,
			0xb00327c898fb213fL, 0xbf597fc7beef0ee4L, 0xc6e00bf33da88fc2L,
			0xd5a79147930aa725L, 0x06ca6351e003826fL, 0x142929670a0e6e70L,
			0x27b70a8546d22ffcL, 0x2e1b21385c26c926L, 0x4d2c6dfc5ac42aedL,
			0x53380d139d95b3dfL, 0x650a73548baf63deL, 0x766a0abb3c77b2a8L,
			0x81c2c92e47edaee6L, 0x92722c851482353bL, 0xa2bfe8a14cf10364L,
			0xa81a664bbc423001L, 0xc24b8b70d0f89791L, 0xc76c51a30654be30L,
			0xd192e819d6ef5218L, 0xd69906245565a910L, 0xf40e35855771202aL,
			0x106aa07032bbd1b8L, 0x19a4c116b8d2d0c8L, 0x1e376c085141ab53L,
			0x2748774cdf8eeb99L, 0x34b0bcb5e19b48a8L, 0x391c0cb3c5c95a63L,
			0x4ed8aa4ae3418acbL, 0x5b9cca4f7763e373L, 0x682e6ff3d6b2b8a3L,
			0x748f82ee5defb2fcL, 0x78a5636f43172f60L, 0x84c87814a1f0ab72L,
			0x8cc702081a6439ecL, 0x90befffa23631e28L, 0xa4506cebde82bde9L,
			0xbef9a3f7b2c67915L, 0xc67178f2e372532bL, 0xca273eceea26619cL,
			0xd186b8c721c0c207L, 0xeada7dd6cde0eb1eL, 0xf57d4f7fee6ed178L,
			0x06f067aa72176fbaL, 0x0a637dc5a2c898a6L, 0x113f9804bef90daeL,
			0x1b710b35131c471bL, 0x28db77f523047d84L, 0x32caab7b40c72493L,
			0x3c9ebe0a15c9bebcL, 0x431d67c49c100d4cL, 0x4cc5d4becb3e42b6L,
			0x597f299cfc657e2aL, 0x5fcb6fab3ad6faecL, 0x6c44198c4a475817L };
}
